Electric water pump with a canned motor

ABSTRACT

An electric water pump with a canned motor is provided. The electric water pump includes a can-integrated volute body and a rotor support. The can-integrated volute body includes a volute body part disposed between a water power part housing and a motor housing and a can part disposed between a rotor and a stator. The volute body part separates a water power part from a driving motor and the can part separates the rotor from the stator. The volute body part and the can part may be integrally formed as one continuous piece and the rotor support is disposed inside the volute body part and rotatably supports the rotor and a motor shaft.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 10-2011-0109754 filed Oct. 26, 2011, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present invention relates to an electric water pump with a canned motor. More particularly, the present invention relates to an electric water pump with a canned motor, in which a can structure is disposed between a rotor and a stator.

(b) Background Art

Water pumps typically circulate cooling water in a vehicle. In a typical vehicle with an internal combustion engine, water pumps may be classified into engine-driven water pumps, which are driven by engine power received through a pulley and a belt and electric water pumps which are driven by electricity.

In an electric water pump, when an electric motor is driven by electricity provided from a battery, an impeller suctions and discharges cooling water while rotating. Since electric water pumps do not need a driving force from an engine, a vehicle's fuel efficiency can be increased by about 2 to 3 percent. Also, since the temperature of cooling water can be precisely controlled, electric water pumps are being applied to mass-produced vehicles manufactured by a number of automobile manufacturers.

Electric water pumps are especially usefully in hybrid vehicles because the engine is not continuously being operated and thus cannot provide a continuous driving force to a mechanical water pump. Also, since fuel cell vehicles or pure electric vehicles are not equipped with an engine which can drive a water pump, electric water pumps are necessary for circulating cooling water.

Alternatively, volute pumps, which are a kind of centrifugal pump, can be used as well instead of electric water pumps in these types of vehicles. The volute pumps include an impeller rotated by an electric motor. When the impeller is rotated by the electric motor, cooling water received through a water inlet at the center of a volute casing is discharged out of a water outlet by a centrifugal force that is generated when cooling water passes a spiral chamber provided in the volute casing. However, most of the time electric pumps are used.

FIG. 1 is a perspective view of an electric water pump with a canned motor. As shown in FIG. 1, the electric water pump with the canned motor includes an electric motor 1 which operates as a driving source, and a water power part 2 generating forces for suctioning and discharging cooling water. The water power part 2 includes a water power part cover 2 a having a spiral chamber, i.e., a spiral floating space, and an impeller 5 rotated by the electric motor 1.

The electric motor 1 generates a rotation force by an electromagnetic interaction between a rotor 3 and a stator 4, and a rotational force is delivered to impeller 5 through a motor shaft 3 a to rotate the impeller 5. The motor shaft 3 a is rotatably supported by bearings 7 disposed on the front and rear sides of the rotor 3 in the housing 6.

The electric water pump with the canned motor has a structure in which cooling water can appropriately cool frictional heat generated in the rotor 3 by inserting a can structure 8 between the rotor 3 and stator 4 and extending the water power part 2 to the rotor part 3 to allow the rotor 3 to be immersed in the water. In this case, the can structure 8 serves as a partition for separating the rotor 3 from the stator 4, and is sealed by a can sealing to rubber between the rotor 3 and the stator 4.

However, it is difficult to fix the front bearing 7 supporting the motor shaft 3 a, and the number of parts increases when a structure of a front bearing 7 is introduced. Also, when water is suctioned by rotation of the impeller 5 due to an electromagnetic force generated between the rotor 3 and the stator 4, water may generate a thrust in the axial direction opposite to the suctioning direction of water, which changes the location of the impeller 5 and thus reduces its efficiency.

Furthermore, since an O-ring for maintaining airtightness between the motor housing 6 and the volute chamber and an O-ring for maintaining airtightness between the water power part cover 2 a and the volute chamber are difficult to position, the manufacturing process becomes difficult, and a balancing process is almost impossible when the impeller 5 is combined with the motor shaft 3 a of the rotor 3.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention.

SUMMARY OF THE DISCLOSURE

The present invention provides an electric water pump with a canned motor configured to fix a front bearing for supporting a motor shaft to one side of a rotor support, by inserting the rotor support into a can-integrated volute body. In particular, the present invention provides an electric water pump with a canned motor that can improve efficiency, by tightly supporting a motor shaft by a rotor support thereby reducing the change in the fixed location of an impeller.

The present invention also provides an electric water pump with a canned motor that can easily position an O-ring compared to the conventional art even when only one O-ring is disposed between a water power part housing and a volute body part, and can measure rotation balancing of a rotor assembly when an impeller is assembled into an assembly of a rotor support and a can-integrated volute body.

In one aspect, the present invention provides an electric water pump with a canned motor including: a can-integrated volute body having a volute body part disposed between a water power part housing and a motor housing. The volute body separates a water power part from a driving motor. The can-integrated volute body also includes a can part disposed between a rotor and a stator to separate the rotor from the stator. Additionally, the volute body part and the can part are integrally formed. Furthermore, the electric water pump with a canned motor of the present invention also includes a rotor support disposed inside the volute body part and rotatably supporting the rotor and a motor shaft.

In an exemplary embodiment, airtightness between the volute body part and the water power part housing may be maintained using an O-ring that is disposed at a contact portion of the volute body contacting an inner surface of the water power part housing, and an edge portion of the volute body part may be coupled in a form of flange between the water power part housing and the motor housing.

In some exemplary embodiments, the rotor support may include a coupling part inserted into one side of the volute body part, a bearing housing part axially disposed in the coupling part to house a bearing fixed therein, and a fluid passage disposed between the coupling part and the bearing housing part to guide a fluid of the water power part to the rotor. Additionally, the rotor support may be clipped to the can-integrated volute body along the groove formed in the can-integrated volute body.

Other aspects and exemplary embodiments of the invention are discussed infra.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given hereinbelow by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a view illustrating an electric water pump with the canned motor according to the conventional art;

FIG. 2 is a cross-sectional view of an electric water pump with a canned motor according to an exemplary embodiment of the present invention; and

FIG. 3 is a perspective view illustrating a rotor support of FIG. 2.

Reference numerals set forth in the Drawings includes reference to the following elements as further discussed below:

-   -   1: motor     -   2: water power part     -   2 a: water power part housing     -   2 b: water inlet     -   3: rotor     -   3 a: motor shaft     -   4: stator     -   5: impeller     -   6: motor housing     -   7 a: front bearing     -   7 b: rear bearing     -   9: O-ring     -   18: volute body part     -   19: can part     -   20: can-integrated volute body     -   21: coupling part     -   22: bearing housing     -   23: rotor support     -   24: fluid passage

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Hereinafter reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, to electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles.

The above and other features of the invention are discussed infra.

The present invention relates to an electric water pump with a canned motor, which is configured to measure rotation balancing of a rotor assembly when the rotor assembly and an impeller 5 are assembled, by applying a structure in which a volute body part 18 and a can part 19 are integrally injection-molded as one continuous piece and a structure in which a rotor support 23 is inserted into a can-integrated volute body 20 to the electric water pump with the canned motor.

The electric water pump with the canned motor may include a water power part 2 for suctioning water using rotation of the impeller 5, and a driving motor 1 for driving the impeller 5. The water power part 2 may include a water power part housing 2 a having a water inlet 2 b at one side thereof and an impeller 5 disposed inside the water power part housing 2 a.

For example, the water inlet 2 b may be a passage for suctioning cooling water into the water pump in a fuel cell vehicle, and may project from the water power part housing 2 a in an axial direction.

The water power part housing 2 a may cover the upper portion of the impeller 5, and may suction cooling water into the water power part 2 through the water inlet 2 b using rotation of the impeller 5.

The driving motor 1 may include a motor housing 6 coupled to the water power part housing 2 a with a bolt, a rotor 3 and a stator 4 generating a rotation force inside the motor housing 6 using an electromagnetic force, and a can-integrated volute body 20 for fully waterproofing the water power part 2.

In this case, the can-integrated volute body 20 may include a volute body part 18 radially disposed between the water power part housing 2 a and the motor housing 6 and a can part 19 extending from the volute body part 18 in the axial direction. The volute body part 18 may serve as a partition for separating the water power part housing 2 a from the motor housing 6. The can part 19 may serve as a partition for separating the rotor 3 from the stator 4. More specifically, the volute body part 18 may be disposed at a boundary between the water power part housing 2 a and the motor housing 6 to prevent water of the water power part 2 from flowing into the stator 4 of the motor housing 6.

For example, the edge portion of the volute body part 18 may be interposed between the water power part housing 2 a and the motor housing 6 in a form of a flange, and may be penetrated and coupled thereto by a bolt. An O-ring 9 may be disposed on the inner side of the flange of the volute body part 18 to maintain airtightness between the water power part housing 2 a and the side surface of the volute body. Thus, water from the water power part 2 can be prevented from flowing into the stator 4 of the motor housing 6.

In the conventional art, since O-rings are disposed between a housing of a water power part and a volute body and between a motor housing and the volute body, respectively, it is difficult to position the O-rings, and the manufacturing cost increases due to increase in the number of parts and man-hours required to assembly the pump. In the present embodiment, however, since the O-ring does not need to be disposed between the motor housing 6 and the volute body part 18, the number of parts and the man-hours required can be reduced, thereby saving manufacturing costs.

The can part 19 may be disposed between the rotor 3 and the stator 4, and may have a cylindrical shape surrounding the rotor 3. The rotor 3 may be sealed by the can part 19. The can part 19 may communicated with the water power part 2, and may provide a fluid passage 24 between the water power part 2 and the rotor 3 to allow water of the water power part 2 to be supplied to the rotor 3.

In some exemplary embodiments, and preferably, the volute body part 18 and the can part 19 may be integrally injection-molded as one continuous piece/part. The rotor 3 may be disposed inside the can part 19, and a motor shaft 3 a may penetrate the rotor 3 so as to rotate together with the rotor 3.

The electric water pump with the canned motor may further include a rotor support 23 for rotatably supporting the rotor 3 and motor shaft 3 a. The rotor support 23 may include a coupling part 21 that is inserted into the volute body part 18 and a bearing housing part 22 that has a smaller diameter. The bearing housing part 22 is disposed in the axial direction to secure a front bearing 7 a for supporting the motor shaft 3 a.

In this case, the fluid passage 24 may be formed between the coupling part 21 and the bearing housing part 22 to communicate the water power part 2 with the rotor 3 through the fluid passage 24. Thus, water of the water power part 2 may be supplied to the rotor 3 to cool heat generated in the rotor 3.

In some embodiments, the coupling part 21 may have a thread on the outer surface thereof. The coupling part 21 may be fastened to the inner side of the volute body part 18 along the thread, maintaining a tight coupling with the volute body part 18.

In other embodiments, the coupling part may have a coupling protrusion on the outer surface thereof. The coupling part 21 may be coupled to the volute body part 18 through clip coupling using the coupling protrusion and a groove in the volute body part 18.

The bearing housing part 22 may have a housing space for housing the front bearing 7 a therein, and the front bearing 7 a may be fixed into the bearing housing part 22 through a press or compression fit. Thus, the front bearing 7 a for supporting the motor shaft 3 a integrally coupled to the rotor 3 can be easily fixed thereto. Also, a rear bearing 7 b for supporting the rear end of the motor shaft 3 a may be fixed to the undersurface of the can part 19.

According to the above coupling structure, when the can-integrated volute body 20 and the rotor support 23 are assembled, that is, the can-integrated volute body 20 housing the rotor 3 and the motor shaft 3 a, the rotor support 23 for supporting the motor shaft 3 a and the rotor 3, and the impeller 5 are assembled, the rotation balancing of the rotor 3 can be measured.

In the case of the can-integrated volute body 20, a separate protrusion may be provided on the outer surface of the can part 19 to secure the can part 19 and the stator 4.

Accordingly, when an electric water pump with a canned motor is applied using the can integrated volute body 20 and the rotor support 23, the water power part 2 and the motor housing 6 can be fully divided.

Also, by adding the rotor support 23 to the can-integrated volute body 20, the assembly of the rotor 3 and the motor shaft 3 a can be tightly supported to prevent shaking or vibrations during rotation by a rotational force generated by an electromagnetic reaction between the rotor 3 and the stator 4.

In addition, when a thrust in the opposite direction to the fluid flow is generated during the rotation of the impeller 5 by a rotational force from an electric motor, the rotor support 23 can prevent eccentric rotation and floating of the impeller 5. Furthermore, since the rear bearing, the rotor 3, the motor shaft 3 a, and the rotor support 23 with the front bearing 7 a inside the volute body part 18 are sequentially assembled into the can part 19 of the can-integrated volute body 20, the assembly efficiency can be improved. Also, balancing work can be performed when the rotor assembly and the impeller 5 are combined with the can-integrated volute body 20.

The invention has been described in detail with reference to exemplary embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents. 

What is claimed is:
 1. An electric water pump with a canned motor comprising: a can-integrated volute body comprising a volute body part disposed between a water power part housing and a motor housing and a can part disposed between a rotor and a stator, the volute body part separating a water power part from a driving motor and the can part separating the rotor from the stator, the volute body part and the can part integrally formed as one continuous piece; and a rotor support disposed inside the volute body part and rotatably supporting the rotor and a motor shaft.
 2. The electric water pump of claim 1, wherein airtightness between the volute body part and the water power part housing is maintained using an O-ring that is disposed at a contact portion of the volute body contacting an inner surface of the water power part housing, and an edge portion of the volute body part is coupled in a form of a flange between the water power part housing and the motor housing.
 3. The electric water pump of claim 1, wherein the rotor support comprises a coupling part inserted into one side of the volute body part, a bearing housing part axially disposed in the coupling part to house a bearing fixed therein, and a fluid passage disposed between the coupling part and the bearing housing part to guide a fluid of the water power part to the rotor.
 4. The electric water pump of claim 1, wherein the rotor support is clipped to the can-integrated volute body along the groove formed in the can-integrated volute body.
 5. An electric water pump with a canned motor comprising: a body comprising a first part disposed between a first housing configured to receive water and surround a water power part, and a second housing surrounding a motor and a second part disposed between a rotor and a stator, the first part separating a water power part from a driving motor and the second part separating the rotor from the stator, the first part and the second part integrally formed as one continuous piece; and a support disposed inside the first part and rotatably supporting the rotor and a motor shaft.
 6. The electric water pump of claim 5, wherein the first part is a volute body part, the second part is a can part, wherein airtightness between the volute body part and the first housing is maintained using an O-ring that is disposed at a contact portion of the volute body contacting an inner surface of the first housing, and an edge portion of the volute body part is coupled in a form of a flange between the first housing and the second housing.
 7. The electric water pump of claim 5, wherein the support comprises a coupling part inserted into one side of the volute body part, a bearing housing part axially disposed in the coupling part to house a bearing fixed therein, and a fluid passage disposed between the coupling part and the bearing housing part to guide a fluid of the water power part to the rotor.
 8. The electric water pump of claim 5, wherein the body is a can-integrated volute body and the support is clipped to the a can-integrated volute body along the groove formed in the can-integrated volute body. 